class Solution {
public:
    vector<int> searchRange(vector<int>& nums, int target) {
        if(nums.size() == 0)
            return {-1, -1};

        vector<int> ret;
        int left = 0, right = nums.size() - 1;
        // 1.寻找左端点
        while(left < right)
        {
            int mid = left + (right - left) / 2;
            if(nums[mid] < target)
                left = mid + 1;
            else
                right = mid;
        }
        if(nums[left] == target)
            ret.push_back(left);    // 等于目标值就是它的左端点
        else
            ret.push_back(-1);

        // 2.寻找右端点
        left = 0, right = nums.size() - 1;
        while(left < right)
        {
            int mid = left + (right - left + 1) / 2;
            if(nums[mid] > target)
                right = mid - 1;
            else
                left = mid;
        }
        if(nums[right] == target)
            ret.push_back(right);   // 等于目标值就是它的右端点
        else
            ret.push_back(-1);

        return ret;
    }
};